Gay Gene

Does The "Gay Gene" Exist?

The debate over the existence of a "gay gene" has been building ever since 1993 when a scientist at the US National Cancer Institute named Dean Hamer looked into the family histories of over 100 gay men and found homosexuality tended to be inherited. The Guardian reports that Hamer found "more than 10% of brothers of gay men were gay themselves, compared to around 3% of the general population. Uncles and male cousins on the mother's side had a greater than average chance of being gay, too."

In his research, Bailey drew blood from 409 gay brothers and straight members of their family. He found that markings on an area of the X chromosome, which men inherit from their mothers, called Xq28 had some bearing on sexual orientation.

Graves says we should think of this gene as a "male-loving" gene rather than a "gay gene" (she also explains that it is not a gene, but a gene variant called an "allele"). This particular male-loving allele is common in females because it predisposes them to mate earlier and more often. But when this allele is passed on to a male, it is no longer evolutionary beneficial because gay men tend to have few children, if any. So why does the gene persist and get passed on so frequently?

In her article, Graves cites an Italian study which showed that the "female relatives of gay men have 1.3 times as many children as the female relatives of straight men." Graves explained: "This is a huge selective advantage that a male-loving allele confers on women, and offsets the selective disadvantage that it confers on men." Thus, for evolutionary purposes, the benefits outweigh the disadvantages and the allele lives on.

The findings regarding Xq28 are in no way conclusive. Many of the gay men Baily drew blood from did not have markings in the Xq28 region. Furthermore, studies of twins have found that that identical twin of a gay man is more likely to be straight than gay. And both Baily and Graves acknowledge that sexual orientation is determined by a combination of factors including genetics, environment, exposure to hormones in the womb and birth order.

For homosexuals, Hamer's and Bailey's research is both vindicating and troubling. It gives proof to the assertion that being gay is not a "choice," but it also opens up the dangerous possibility of prenatal tests for sexual orientation, which in the wrong hands could be disastrous.

For now, more research is required to prove the existence of the "gay gene," but with these threats in mind, it may be better to put more focus on abolishing discrimination against homosexuals first.

The Guardian quoted Steven Rose of the Open University who said: "What worries me is not the extent, if at all, to which our genetic, epigenetic or neural constitution and development affect our sexual preferences, but the huge moral panic and religious and political agenda which surrounds the question."